Trimmer mechanism



Nov. 15, 1927. 1,649,093

J. A. BOUSLOUGH ET AL TRIMMER MEOHANISH Filed F613. 20. 1924 2Sheets-Sheet 2 IN VENTORS Joseph A Bous/auq/i and George /7. fab/vATTORNEY wnurassss: 3.53%

Patented Nov. 15, 1927.

UNITED STATES .PATE

NT FF C JOSEPH A. BOUSLOUGI-I Ann GEORGE m. EATON, or wrnxrnseune,PENNSYLVANIA,

.ASSIGNORS TO WESTINGHOUSE ELECTRIC &

PORATION OF PENNSYLVANIA.

MANUFACTURING COMPANY, A. COB- TRIMMER MECHANISM.

Application filed February 20, 1924. Serial No. 694,163.

Our invention relates to trimming means for gear grinding wheels andmore particu larly to mechanisms for trimming the tooth contour formingwheels utilized in the grinding of gear teeth.

It is among the objects of our invention to provide a trimmer mechanismwhich shall be of simple, compact and durable mechanical constructionand which shall be applicable to the trimming of gear grinding abrasivewheels of any involute tooth form and for any pitch of gear tooth thatit is desired to grind.

Other objects of our invention are to provide a trimmer mechanism whichmay be conveniently adjusted to accurately form or trim the abrasivewheel in a simple manner, which shall not require a skilled operator forits manipulation and adjustment, and which shall embody the use of asingle abrasive cutting tool such as a diamond, for trimming-both facesof the abrasive wheel.

Various types of trimmer mechanism have been utilized for trimmingabrasive wheels employed for grinding gear teeth which function by meansof engagement with a cam member of the shape of the gear tooth to beground. One type of cam trimming device has embodied a relatively largecam or template having an engaging surface of substantially involutecurve shape and which was co-operatively engaged by an extensiblepantograph frame structure that carried the trimmer to effect areduction to the normal size of the gear tooth for which the abrasivewheel was adapted. This involved a rather indirect functioning of themechanism which resulted in inaccuracies.

Our present invention is directed to a device for trimming gear grindingwheels trimmer holder and cylindrical block arepivotally mounted on abase to adapt them for swivel movement through an arc of 180, whichpermits of. utilizing the same trimmer on both sides of the wheel.

In the accompanying drawing, constituting a part hereof, and in whichlike reference characters designate like parts,

Figure 1 is a view, artially in section and partially in elevation, of atrimmer mechanism embodying the principles of our invention;

Fig. 2 is a view, partially in section and partially in elevation takenalong the line II-II of Figure 1,

Fig. 3 is a top plan view thereof, and

i Fig. i is a fragmentary view, partially in section and partiallyinelevation showing the manner of securing the trimmer holder to thebase cylinder.

Referring to Fig. 1, the structure therein illustrated comprises a base1 having openings 2 by which it is adapted to be secured to a grindingmachine. The base 1 is provided with a central opening 3 and a counterbore 4 that is adapted to receive a central projecting portion 5 of acenter plate 6. The center plate 6 is provided with an opening 7which'registers withthe opening 3 of the base 1, and a bolt 8 isprojected therethrough to pivotally secure the center plate on thebasel. A saddle block 9 is slidably mounted on the center plate 6 bymeans of a screw shaft 10 on the plate 6 and having threaded engagementwith a depending portion 11 of the saddle 9. The end of the screw 10 isextended through an opening 12 of the center plate 6, and is providedwith a ring 13 that is secured thereto, to restrain axial movement ofthe shaft 10, and to permit rotative movement thereof.

The saddle block 9 is provided with a cylindrical portion 14: having amagnet coil 15 disposed thereonand insulated therefrom by suitableinsulating material 16. Cylindrical segments 17 and 18 are secured tothe respective'side's of the block 9 by means of bolts 20. A grid member21 having a handle portion 22 and a central grid 23 (Fig. 3), is

mounted on the segments 17 and 18 by means of a plurality of straps 24,(Fig. 4) one end of each strap being secured to the cylindrical segmentsand the other end to the grid member.

The straps24' are preferably of non-ferrous substance, such'as copper orphosphorbronze, preferably the latter. The object of fastening the grid21 by the straps 24 to the cylindrical segments as shown, is to permitoscillatory movement of the handle 22 so that a point taken on thehorizontal axis of the grid member will describe an involute curve whenthe handle 22 is actuated. A trimmer 26, such as a cutting diamondproperly set in an adjustable holder, such as a set screw 27, is securedin the center of the member23 and is provided with a lock nut 28 tomaintain adjustment of the screw 27.

A centering block 29 of hardened steel or other suitable material issecured to the segments by screws 30 and the relative position of thetrimmer 26 and the abrasive wheel 32 to be trimmed is adjusted bybringing said trimmer in engagement with the center block 29.

The center plate 6 is provided with a shoulder 33 to actas a-stop forthe extended base portion 34 of the saddle 9. When the shoulder 33 andthe portion 34 of the saddle are in engagement, the edge 37 of thecenter block 29, the center of the segments 17 and 18, and thecenterline of the center plate 6 are all in the same vertical plane. Anadjustment gage 35, that is e ual in thickness to one half of thechordal istance between the intersection of the involute curves of thetwo sides of the grinding wheel and the base circle of said involutecurves, is inserted between the shoulders 33 and 34. The diamond point26 is set against the face 37 of the center block 29 with the grid in ahorizontal position. The extension 40 of the saddle 9 limits themovement of the grid 21 so that when the grid engages the extension 40,it is in a horizontal position.

The segments 17 and 18, and the straps 24 are'so proportioned that theradius of the segments plus half the thickness of the straps 24constitutes the radius of the base circle of the tooth form to begenerated on the wheel 32. The abrasive diamond 26 is set centrally withthe center of the straps 2L and the grinding wheel 32 is adjusted rela-'tive thereto to obtain the proper chordal distance on the periphery ofthe wheel when the trimmer operates.

\Vith the grid 21 in a horizontal position, the diamond or trimmer 26 isbrought into engagement with the block 29 by adjusting the screw 27 andit is then in working position to trim or dress the rotating wheel 32 byactuating the handle 22 of the grid. The oscillatory angular movement ofthe grid handle produces a rolling motion of the grid 21 causing thetrimmer 26 to describe an in- Vdlute-curve that is reproduced on theabrasive wheel 32.

After trimming one side of the wheel, the center plate 6 and the saddleblock 9 are rotated 180 on the pivot bolt 8 and the operation isrepeated by bringing the trimmer 26 into engagement with the othersurface of the abrasive wheel.

During the trimming operation the magnet 15 is energized to set up aflux in the cylindrical member 43 which passes through the side portionsof the grid 21, thus tending to attract the latter to provide thenecessary contact with the segments 17 and 18 and the non-ferrous strips24 act as insulating liners to prevent binding of the grid and segments.

It is evident from the foregoing description of our invention that atrlmmer mechanism made in accordance therewith provides a simple andefiicient means for accurately trimming and forming the involute facesof abrasive wheels for grinding gear teeth, and a further advantage isobtained by making the trimmer mechanism rotatable on its base so thatthe trimmer may be used on both sides of the wheel. The use of the sametrimmer for both faces of the wheel produces the same degree of accuracyon both cutting faces of the grinding wheel which is a desirablecondition for the reason that it results in uniform tooth profiles onthe ground gear wheels.

, Although we have described a specific embodiment of our invention, itwill be obvious to those skilled in the art that various modificationsmay be made in the details of construction and the design andproportions of the several cooperating parts comprising our trimmerdevice, without departing from the principles herein set forth.

We claim as our invention l. A trimmer mechanism for abrasive wheelscomprising a base member, a plurality of cylindrical segments mountedthereon, means for turning said segments relative to said base member,agrid member mounted on said segments, a trimmer secured to said grid andmeans for rolling said grid on said segments.

2. A trimmer mechanism for abrasive wheels comprising a base member, aplurality of cylindrical segments secured thereto, a grid member mountedon said segments, a trimmer secured to said grid and means for rollingsaid grid on said segments, said means comprising a plurality of strapssecured to said grid and segments.

3. A trimmer mechanism for abrasive wheels comprising a base member, aplurality of cylindrical segments secured thereto, a grid member mountedon said segments. a trimmer secured to said grid and means for rollingsaid grid on said segments, said means comprising a plurality of strapssecured at one of their ends to said segments and at their other ends tosaid grid.

4. A trimmer mechanism for abrasive wheels comprising a base member, aplurality of cylindrical segments adjustably secured thcrcto a gridmember mounted on said segments, a trimmer secured to said grid andmeans for rolling said grid on said segments, aid 111 .3113 QOIIIPIlSlDgt1. plurality of straps secured to said grid and segments.

5. A t rimmermecha n ism for abrasive wheels comprising a base member, aplurality of cylindrical segments secured thereto, means for adjustingsaid segments relative to said base member, a. grid member mounted onsaid segments. a trimmer secured to said grid, means for rolling saidgrid on said segments, and means for holding said grid against thesegments.

6. A trimmer mechanism for abrasive Wheels comprising a base member, aplurality of cylindrical segments secured thereto, a. grid membermounted on said segments, a trimmer secured to said grid, means forrolling said grid on said segments, and mag netic means for holding saidgrid against the segments.

7. A trimmer mechanism for abrasive Wheels comprising a base, segmentssecured thereto. a grid mounted on said segments, a trimmer secured tosaid grid, magnetic means for holding said grid against said segmentsand non-ferrous straps secured to the grid and segment members.

8. A trimmer mechanism for abrasive wheels comprising a base, segmentssecured thereto, a grid mounted on said segments, a trimmer secured tosaid grid, magnetic means for holding said grid against said segments.non-ferrous straps secured to the grid and segment n'ieinbers andadjusting means for said trimmer. i,

9. A trimmer mechanisn'i for abrasive wheels, comprising a base,segments secured thereto. a grid mounted on said segments, a trimmersecured to said grid, magnetic means for holding said grid against saidsegments, non-ferrous straps secured to the grid and segment members,and means for adjusting said trimmer relative to said grid.

10. A trimmer mechanism for abrasive wheels comprising a base, segmentssecured thereto, a grid mounted on said segments, a

trimmer secured to said grid, magnetic means for holding said gridagainst said segments non-ferrous straps secured to the grid andsegmentmembers, means for adjusting said trimmer relative to said gridand means for adjusting said grid relative to the said base.

11. A trimmer mechanism for abrasive wheels comprising a base, acylindrical block pivotally mounted thereon, a plurality of segmentssecured to said block, a grid member mounted on said segments, strapssecured at their ends to said grid and segments, at trimmer adjustablymounted in said grid, a magnet coil in said block, means for energizingsaid coil to establish a magnetic held in said segments and grid,adjusting means for said block relative to said base and means forrotating said block 180.

12. A trimmer mechanism for abrasive wheels comprising a base, aplurality of segments mounted on said base, a grid member oscillatablymounted on said segments,

straps secured to said grid and segments,

and a trimmer mounted in said grid, said segments having a radius equalto the radius of the base circle less half the thickness of said straps.

13. A trimmer mechanism for abrasive wheels comprising a pivotal base, aplurality of segments mounted on said base, a grid member oscillatablymounted on said segments, straps secured to said grid and segments, anda trimmer mounted in said grid, said segments having a radius equal tothe radius of the base circle less half the thickness of said straps.

14. A trimmer mechanism for abrasive wheels comprising a base, aplurality of segments removably mounted on said base, a grid memberoscillatably mounted on said segments, straps secured to said grid andthe radius of the base circle less half the thickness of said straps,and thegenerating surface of said trimmer being part of a circularcylinder.

In testimony whereof, We have hereunto subscribed our names this 13thday of February 1924.

JOSEPH A. BOUSLOUGH. GEORGE M. EATON.

segments and a trimmer mounted in said. grid, said segments having aradius equal to

